I talked to some jelly keepers and came up with some new methods of keeping the ephyra.
Method 1 ( failed method)
I used a 500 ml glass graduated cylinder. This cylinder had a bubble tube circulating the water. Lighting came from a desk lamp with a compact fluorescent bulb in it. Water temp was at ambient, room temp likely.
Method 2 (current try)
I'm using the same graduated cylinder. This time I have a 12" strip of 20,000 kelvin white LED lights attached to the top and sides. The cylinder is set in another aquarium which is at 80 degrees F. I change the water every day. The cylinder is sitting in a 44 gallon corner tank, which I later plan on putting cuttlefish in. A canister filter and 150 gallon protein skimmer is running. I just exchange water between the tank and the cylinder daily. My hope is that the heavy filtration removes the negatives, but allows the benefits of a cycling tank. It may simulate an ocean more closely than 500 ml of water.
The major things I was told to change were lighting and temp. I've kept Upside Down Jellyfish at room temp. and seen so adverse effects. For proper zooxanthellae growth, a temp of 80 F or above is preferred. Lagoon Jellyfish ephyra are born very small compared to Upside Down Jellyfish, so algae food is the most important, as they may be unable to catch Brine Shrimp efficiently. A desk lamp probably won't do it, but I figured I could improve on lighting when they got older. Now I've decided to go ahead an get the improved lighting. There is debate about whether LEDs can match good old fashion metal halide lighting. I think LEDs will do the job. I certainly hope so, as they are much more energy efficient, space efficient, and cooler. If this works out, I plan on buying longer strips of lighting. If not, I probably need to try metal halides.
My current set up. The bright cylinder is where the lagoon ephyra are kept (3 of them right now). The plastic bottle is a brine shrimp hatchery. It's too cold in the garage for them to hatch in ambient temperature. The protein skimmer is also pictured. White light is coming from the LEDs and orange light from the desk lamp.
Results: the second set up has worked. The good temp, light and daily water changes seem to do it. I've raised two batches of lagoon jellies so far. The first batch of jellies tipped over though (oops! :p). The second batch is being raised now. I have 15 total ephyra. I'm hoping these will go to adults! More progress soon :)